Mongodb聚合从文档内部检索文档 [英] Mongodb aggregation retrieving document from inside of document

问题描述

我对MongoDB的聚合有疑问。

I have problems with MongoDB's aggregation.

在我的作业文档中，它具有creatorParent（单个值）和Children（由mongodb对象ID组成的数组）。在用户文档中，用户具有带有子级详细信息的子级数组。

In my "Job" document, it has creatorParent(single value) and Children(array of mongodb object id). In the "User" document, user has children array with child details.

当用户请求检索此文档时，如果数组包含child的ID，我希望汇总子级详细信息。

When user request for retrieving this document I want aggregate child details, if array contains id of child.

我在一些帮助下编写了一个汇总，它适用于creatorParent，但无论我如何尝试，都不适用于儿童。

I wrote an aggregation with some help, It worked for creatorParent but whatever I've tried, it didn't worked for children.

db.getCollection('Jobs').aggregate([
    {
        $unwind: {
            path : "$children"
        }
    },
    {
        $lookup: {
            "from" : "Users",
            "localField" : "creatorparent",
            "foreignField" : "_id",
            "as" : "creatorparent"
        }
    },
    {
        $lookup: {
            "from" : "Users",
            "localField" : "children",
            "foreignField" : "children",
            "as" : "children"
        }
    }
])

用户文档：

{
    "_id" : ObjectId("58daf84877733645eaa9b44f"),
    "email" : "[e-mail]",
    "password" : "vpGl+Fjnef616cRgNbCkwaFDpSI=",
    "passwordsalt" : "99397F4A9D3A499D96694547667E74595CE994D2E83345D6953EF866303E8B65",
    "children" : [ 
        {
            "_id" : ObjectId("58daf84977733645eaa9b450"),
            "name" : "Mert",
            "age" : 5,
            "additionalinformation" : "ilk cocuk",
            "creationtime" : ISODate("2017-03-28T23:56:56.952Z"),
            "userid" : ObjectId("58daf84877733645eaa9b44f"),
            "gender" : null
        }, 
        {
            "_id" : ObjectId("58daf84977733645eaa9b451"),
            "name" : "Sencer",
            "age" : 7,
            "additionalinformation" : "ikinci cocuk",
            "creationtime" : ISODate("2017-03-28T23:56:56.952Z"),
            "userid" : ObjectId("58daf84877733645eaa9b44f"),
            "gender" : null
        }
    ]
}

工作

{
    "_id" : ObjectId("58db0a2d77733645eaa9b453"),
    "creationtime" : ISODate("2017-03-29T01:13:17.509Z"),
    "startingtime" : ISODate("2017-04-03T13:00:00.000Z"),
    "endingtime" : ISODate("2017-04-03T17:00:00.000Z"),
    "children" : [ 
        ObjectId("58daf84977733645eaa9b450"), 
        ObjectId("58daf84977733645eaa9b451")
    ],
    "creatorparent" : ObjectId("58daf84877733645eaa9b44f"),
    "applicants" : []
}

推荐答案

尝试一下：

db.jobs.aggregate(
    [
        {
            $unwind: {
                path : "$children",
            }
        },
        {
            $lookup: {
                "from" : "users",
                "localField" : "creatorparent",
                "foreignField" : "_id",
                "as" : "creatorparent"
            }
        },
        {
            $lookup: {
                "from" : "users",
                "localField" : "children",
                "foreignField" : "children._id",
                "as" : "children"
            }
        },
        {
            $addFields: {
                children : {$arrayElemAt : ["$children",0]}
            }
        },
        {
            $addFields: {
              "children":"$children.children"
            }
        },
        {
            $unwind: {
                path : "$children",
            }
        },
        {
            $group: {
                "_id": "$_id",
                "name": { "$first": "$name" },
                "jobstatus" : { "$first": "$jobstatus" },
                "hourlyrate" : { "$first": "$hourlyrate" },
                "creatorparent" : { "$first" : "$creatorparent" },
                "children": { "$addToSet": "$children"  }
            }
        },

    ]
);

这篇关于Mongodb聚合从文档内部检索文档的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！